Binocular having externally accessible filter guide



m 1966 R. w. DOWLING ETAL 3,247,763

BINOCULAR HAVING EXTERNALLY ACCESSIBLE FILTER GUIDE Original Filed Aug.31, 1961 7 Sheets-Sheet 1 INVENTORS ROBERT WHITTLE DOWLING LORENZODEIRICCIC BY ALBERT GOLDHAMMER m, fob-Mada @alam ATTORNEYS April 26,1966 R. w. DOWLING ETAL 3,247,763

BINOCULAR HAVING EXTERNALLY ACCESSIBLE FILTER GUIDE Original Filed Aug.51, 1961 7 Sheets-Sheet 2 INVENTORS ROBERT WHITTLE oowuwe LORENZODeiRlCCIO BY ALBERT GOLDHAMMER w, jaw 44 Warm 3 4. 4%,,

AT ORNEYS April 26, 1966 w, DOWLlNG ETAL 3,247,763

BINOCULAR HAVING EXTERNALLY ACCESSIBLE FILTER GUIDE Griginal Filed Aug.31, 1961 '7 Sheets-Sheet 4 INVENTORS ROBERT WHITTLE DOWLING LORENZODelRlCCIO ALBERT GOLDHAMMER PM, W WUJT: AA @1 ATTO N April 1966 R. w.DOWLING ETAL 3,247,763

BINOCULAR HAVING EXTERNALLY ACCESSIBLE FILTER GUIDE 7 Sheets-Sheet 6Original Filed Aug. 31, 1961 INVENTORS ROBERT WHITTLE DOWLING LORENZODel RICCIO a. jLBitRlglOLDfismER 7 ATgORNEYs April 1966 R. w. DOWLlNGETAL 3,247,763

BINOCULAR HAVING EXTERNALLY ACCESSIBLE FILTER GUIDE Original Filed Aug.31, 1961 7 Sheets-Sheet 7 FIG. 16

INVENTORS ROBERT WHITTLE DOWLING LORENZ? Dgl RICCIO Y ALB R G LDHAMMER@uvw), fall/W60 firm uvl f k @11 ATT RNEYS United States Patent3,247,763 HAVING EXTERNALLY AQCEdSIELE GUIDE Robert W. Dowiing, NewYork, NFL, Lorenzo Del Riccio,

Les Augeles, Calif'., and Albert Goldhamrner, Nussdorf, Badentlliodensee), Germany, assignors to D and '1) \Company, Inn, New York,N.Y., a corporation of Delaware firiginal application 31, 1961, Ser'.No. 135,182. Divided and this application Aug. 16, 1963, Ser. No. scams6 Claims. (U. lid-35) This is a division of application Serial No.135,182, filed August 31, 1961.

This invention relates to binocular telescopes and specifically toimprovements in filters and their actuating mechanisms.

The invention herein illustrated and described is incorporated in abinocular having two fiat box-like lens casings mounted for transverseslidable movement upon a connecting central bridge. The lens casings aremovable from a closed position wherein they completely envelop thecentral bridge to positions where the lens casings are movedtransversely outwardly to provide interpupillary distance accommodation.The binocular thus presents a flat oblong shape which is easily carriedor handled and may, when closed, be conveniently slipped into pocket orpurse without the necessity of having a specially molded carrying case.

A binocular of the type described finds its greatest use as a sportsglass or theater glass. Consequently, it is advantageous to make theobjective lenses of the binocular of a generally rectangular outline andof greater width than height. This arrangement permits of a relativelywide or panoramic field of view while sacrificing only the field of viewin a vertical direction, in which direction it is not generally neededfor theater or sports use.

The present invention concerns certain novel arrangements whereinoptical filters may be selectively brought into the light path in orderto make possible or more convenient the viewing of certain events underconditions of extreme brightness or glare.

In combination with the foregoing are provided certain novel binocularconstructions which form the subject matters of co-pending applicationsone of which concerns the arrangement of the optical elements within abox-like lens casing in a manner such that the overall height of thebinocular may be reduced to a minimum. This is effected by inclining theplanes of the light path through a casing with respect to a horizontalaxis or axis of symmetry of the casing. In addition to reducing theheight of the casing, a further advantage of the arrangement is that thebinocular may be declined somewhat when in use, which makes thebinocular easier and less tiresome to hold.

Another aspect of the binocular involves novel means for mounting theoptics of binocular lens systems and for providing movement of portionsof the lens systems to effect focusing for each eye individually or inunison. One of the reflecting members of each binocular optical systemis movable parallel to the optical axes to vary the distance which thelight travels within a lens system. Thus, the compact shape of thebinocular is unaltered by focusing adjustments since these occur bymoving parts internally mounted within each lens casing.

Means are also provided in cooperation with the focusing mechanism topermit the user of the binocular to register, by a detent device, theposition of long range focus adjustment. It, therefore, the owner of thebinocular Wishes to readjust the focus for short range viewing,

he can return to the long range focus position by turning the focusingknob until he notices an appreciable resistance, which is the registereddetent position.

A further aspect of the disclosed binocular is the provision of slidablelens shutters for each of the lenses of a lens system, which shuttersare automatically extended over the lens apertures when the casings aremoved to closed positions. The shutters automatically uncover the lensapertures upon movement of the lens casings to a minimum interpupillarydistance.

In the following description reference is made by way of a non-limitingexample to one form of construction of a binocular devised in accordancewith the invention, and illustrated in the accompanying drawings inwhich:

FIG. 1 is a perspective view showing the binocular of the presentinvention with the lens casings thereof in their closed positions andwith the lens shutters shown covering the ocular enses thereof;

FIG. 2 is a view similar to FIG. 1 showing the lens casings in theiropen positions for interpupillary distance accommodation;

FIG. 3 is a perspeetive view showing the arrangement of the opticalelements within a single lens system;

FIG. 4 illustrates the manner in which the optical elements of a lenssystem are tilted respective of a hori- Zontal axis through a lenscasing;

FIG. 5 is a plan view of the binocular of the FIG. 1 showingparticularly elements of the lens casing and the intermediate centralbridge permitting their relative slidable movement, and also elements ofthe lens cover actuation mechanism;

FIG. 6 is a side elevation of the binocular illustrated in FIG. 5;

FIG. 7 is a cross-sectional view taken substantially along line 7-7 ofFIG. 5;

FIG. 8 is a cross-sectional view taken substantially along line 8-8 ofFIG. 5;

FIG; 9 is a cross-sectional view taken substantially along line 99 ofFIG. 5;

FIG. 10 is a detailed view in the direction indicated by arrows 1l 1fiof FIG. 5, disclosing the actuation mechanism for a lens filter;

FIG. 11 is a view similar to FIG. 10 with the lens filter in position tocover an ocular lens;

FIG. 12 is a cross-sectional view taken substantially along line 1212 ofFIG. 11;

FIG. 13 is a transverse cross section view taken substantially alongline 13-13 of FIG. 5, illustrating various interrelated portions of thefocusing mechanism within the central bridge member;

FIG. 14- is a vertical longitudinal cross section of the central bridgenormal to the optical axes taken along line 14-44 of FIG. 13;

FIG. 15 is a horizontal longitudinal cross section of the central bridgetaken along line 15-15 of FIG. 13;

FIG. 16 is a vertical cross section illustrating the focusing knob andelements of the focus detent mechanism taken along line 16-16 of FIG.15;

FIG. 17 is an exploded view of the elements illustrated in FIG. 16;

FIG. 18 is a section view taken along line 1318 of FIG. 16.

Referring now to the drawing and specifically to FIGS. 1 and 2, abinocular It) has been illustrated which incorporates the severalfeatures of the invention. The binocular 10 has lens casings 11, 12which are mounted for slidable transverse movement upon aninterconnecting central bridge support 13. The degree of such movementfor individually interpupillary distance accommodation may be recordedby noting the position of the casings relative to vertical indicia onthe support (FIG. 5). The

binocular has ocular lens apertures 15 formed within each casing andocular lens units 16.

The central bridge 13 comprises an elongate member having symmetricalarms 18, 19 (FIGS. 5 and 6) which extend into each of the lens casings11 and 12. The arms 18, 19 are each of U-shaped cross section to presentupper and lower portions thereof which are outside of the field of sightwithin a casing. Each casing is box-like in form, including a main frameor housing structure 42 having a generally hollow interior for mountingthe various optical elements of a lens system, as will be describedpresently. The housing 42 mounts guide rails 20 which slidably receivethe upper and lower portions of the U-shaped arms 18, 19 for permittingthe lens casings to be moved outwardly along the central support.

Lens shutters Each of the arms 18, 19 is attached by screws to cambrackets 21, each of which has a recess bounded by surfaces 22, 23 and24. The lens casings each mount a telescoping actuating arm 26 rotatableabout pivot 27. The ends of the arms 26 are pivotally connected at 28and 29 respectively to lens shutters 30, 31 which are slidable withinrecesses 32, 33 within the lens casings. The shutters are plates whichmay be stamped to have embossed thereon a vertical segment whichsimulates louvered construction. The lens shutters 30, 31 have U-shapedupper and lower edges 30a, 31a respectively which in effect form groovesfor receiving ridges 34 forming part of the lens casing structure (seeFIG. 7). The ridges 34 and U-shaped sections 30a, 31a of the lensshutters comprise a means for guiding the lens shutters during theirslidable movement within the recesses 32 and 33.

The arms 26 each mount a pin 26 which cooperates with the cam bracket 21to rotate the arms 26 about pivot points 27, thus causing slidingmovement of the lens shutters 30, 31. If, for example, the arm 18 wereto move into the lens casing 11, the pin 26' would first contact surface24 of the cam bracket 21 attached to arm 18. Further movement of the arm18 into the casing 11 would cause counter-clockwise rotation of the lensshutter actuating arm 26 about pivot 27. The arm 26 would then movesimultaneously each of the lens covers 30, 31 across the related lensapertures in the direction of the arrows. During this entire movement,the pin 26' is in contact with the surface 24 of the cam bracket 21 buttends to move up 'into the slot to the position illustrated in the righthand portion of FIG. 5 with respect to lens casing 12.

When a lens casing is moved outwardly along the central support, thesurface 23 of each cam bracket 21 hooks against its respective drive pin26 by reaction of the pin against surface 23 of the cam, to pull thedrive pin and to cause reverse rotation of the arms 26 for effectinguncovering of the lens apertures. The movement of the lens shutterstherefore will begin immediately upon outward movement of the lenscasings and continues to a position of minimum interpupillary distanceaccommodation at which point lens covers are completely shifted awayfrom the lens apertures. The construction of the cam bracket 21 and thelocation and movement of the pin 26 is such that when the shutters arecompletely withdrawn from the lens apertures, the pin 26' will move outof the slotted portion of the bracket 21 and slide against the straightsurface 22 of the cam bracket, thereby effectively uncoupling thebracket from the pin. Upon return movement of the lens casings topositions approximating a minimum interpupillary distance, the surfaces24 of each cam bracket will engage the respective pins 26 and theshutters will be moved over the lens apertures.

In order to assure equilateral displacement of each of the lens casing11 and 12 with respect to the central bridge each of the casings mountsa rack strip 36 whose teeth mesh with a freely rotatable pinion 37mounted to the central support (FIGS. 5, 13, 14). Thus, when the lenscasings are displaced from their closed positions, the displacement ofone casing will be equal to the displacement of the other. It will beunderstood that the central support 13 includes stops (not shown) whichabut portions of the lens casings and which terminate or limit theoutward movement of the casings.

Lens optical filters According to another feature of the presentinvention, optical filters are provided which may be selectively movedacross the optical axis in each casing to protect against glare, strongsunlight, etc. With reference particularly to FIGS. 7, 8, 10, 11 and 12,a filter frame 35 having front and side portions 35a, 35b is providedwhich holds an optical filter 38. The frame 35 is slidable in adirection normal to the'optical axis and is guided in such movement byboth a rearward tang 35c which slidably engages the edge of a groove 40in the ocular lens mount and the walls of a slot 40a formed in the outerportion of the ocular lens unit 16. A button receptacle 41 is slidablein a vertical groove 42 in the housing structure 42. A pin 41' (FIG. 7)extends from the button receptacle 41 into a slot 43 formed in the side3512 of the filter frame 35. This arrangement permits the filter frame35 to follow a path normal to the inclined optical axis and the buttonreceptacle 41 to move in a true vertical direction. The outer end of thebutton receptacle is connected to a semicircular disc 45 which mounts apin 46. Outwardly of the disc 45 and adjacent thereto is a plate 47attached to the housing structure 42 by means of screws 48. The plate 47has a slot 47' which receives the pin 46 and consequently, when thebutton receptacle 41 is moved vertically, the disc 45 will be forced topivot within the slot 47' of the plate 47.

An actuating button 44 is mounted within the receptacle 41 and isnormally urged outward by a spring 41" therein (see FIGS. 10, l1 and12). The button protrudes through a vertical slot 47" in the plate 47and through a similar aligned slot 39' in an outer cover plate 39. Whenthe casings are in closed closely adjacent positions, however, thebutton 44 will be urged against the spring and into the body of thereceptacle 41.

The semicircular .disc 45 has a rounded inner edge portion which pressesagainst a rounded leaf spring number 49. The construction andrelationship of the spring 49 and disc 45 is such that the disc willurge the receptacle 41 into one or the other of its end positions andwill act as an over-center resilient actuator upon release of the buttonin an intermediate position. An additional valuable function of the disc45 is to slide intermediate the housing structure 42 and the outerplates 47 and 39, each of which is grooved or slotted to provide passagefor the button 44. During such sliding movement of the disc 45, therespective groove and slots will be covered by the disc against thepossible ingress of dirt or other foreign materials into the casing.

Binocular lens system With reference to FIGS. 3, 4, 8, 9 and 12 it willbe observed that the light path proceeds through the objective lens 50and is reflected by the mirror 51 at right angles to its initialdirection. A prism 52 then receives the light, reflects the lightforwardly at a right angle to a first reflecting surface 53a of thesecond prism 53. The surfaces 53a reflects the beam of light upwardly tobe reflected again rearwardly by a second surface 53b, from which thelight proceeds through the ocular lens unit 16.

It will be observed with reference specifically to FIG. 4 that each ofthe optical units are arranged to cause the planes of the light path tobe inclined with respect to a reference plane or axis of symmetrypassing generally parallel to and intermediate the top and bottom wallsof a lens casing, whose outline has been indicated in solid line. Theobjective and ocular lens units are however, arranged substantiallyalong the axis of symmetry of the casing, consequently, the height ofthe casing is less than if the lens elements were mounted in theconventional manner (as indicated by the dotted outline) sorthat theplanes of the light path are parallel to the top and bottom of a casing.

A further advantage to the disclosed arrangement is that during theviewing of an event, the binocular may be downwardly inclined (solidline position of FIG. 4) which position is more restful to the arms ofthe user.

With reference to FIG. 3, it may be observed that the prism 53 ismovable in a direction parallel to the light path as indicated by thearrow. As will be described presently with specific reference tostructural details, the prism 53 is movable in order to provide focusingadjustment of each lens system. When the prism 53 is moved, the distancewhich the light must travel between ocular and objective lenses isincreased or diminished to vary the focus.

The prism 53 need be moved only one-half the distance which wouldordinarily be necessary for movement of an ocular lens unit, forexample, in systems where the ocular lens is movable to providefocusing. Consequently, less focusing adjustment is required and thecasing may be better sealed against the ingress of dust or other foreignparticles than would be possible where the ocular lens unit is movable.

Proceeding now to the structural details of the aforementioned lenssystem, we refer specifically to FIGS. 7-9 and 14- and 15. Withreference to FIGS. 79, the objective lens unit fill is inclined slightlywith its upper edge toward the rear of the casing and is held securelywithin a lens mount 5'5 secured to frame 42. Light passes through theobjective lens to the mirror 5i. and from the mirror to the prism 52(FIGS. 8 and 12) and therefrom in a forward direction to the movableprism 53. The prism 53 reflects the received light both upwardly andrearwardly through the ocular lens unit 116. Prism 53 is attached bycement to, or is made integral with a mount 53. Attached to the mount 58is a shaft 59 which is slidable within a bore 6t? formed within theframe 42'. The end of shaft 59 is tapped to receive a threaded screw 61.Between the head of the screw and an abutment shoulder 62 defined by theframe 4-2, a helical spring as is disposed tending to bias the shaft 59toward th forward or objective lens portion of the frame 42. The prism53 may be shifted toward the rear of the casing by means of a cam 63(FIGS. 7, 14 and whose outer periphery is in the form of an Archimedesspiral: The cam 63 may be rotated by a rectangular-shaped shaft 64 andwhen such rotation takes place, the surface of the cam will thrust themount 58 and prism 53 toward the ocular lens 16. The spring 65 providesa return action.

Focus adjustment With reference to FIG. 15, an externally operablefocusing wheel 66 is connected to a drive shaft 67 by means of an oblongslot 6% (FIG. 16) and the screw 70. The drive shaft 67 therefore rotateswhenever the focusing wheel 66 is rotated. At its lower end, the shaft57 comprises a bevel gear 71 which meshes with a second bevel gear '72rotatable within a clutch housing 6%. The housing is fixed to thecentral bridge 13 and the gear '72 has attached thereto amember 72forming part of a clutch generally designated by numeral 74. Radialserrations 72" normally engage similar sections 73 on a movable member73 of the clutch. The movable member 73 is biased against the member 72by a spring 75. The spring 75 is seated in a counterbore in a journal 76which is retained by means of the screws '77.

The members 72, '73 are hollow to receive the hooked ends 64- of tworectangular-shaped drive rods Opposite ends of the rods 64 extend intothe frame or housing %2 of each casing, and as shown in the right handconnection with the hubs portion of FIG. 15 connected with one of thecams 63. The latter are mounted by the screws 79 to hub fill and each ofthe rods 64 is slidable with respect to its hub such that when thecasings are in their closed positions, the ends of the rods extend for adistance beyond their The hooked ends 64 of the rods dd within theclutch elements "720 and 73, prevent removal of the rods therefrorn'byfrictional forces when the lens casings are moved outwardly relative tothe central bridge 13. A tubular member 73 is located within the clutch74 and acts as a stop against which ends 64 of the rods 64 abut when thelens casings are moved to closed positions. he free ends of the rod 64opposite to the inner hooked ends 6 extend from the hubs 30 a sumcientdistance to remain in engagement with the hubs in all positions of thelens casings.

The invention also provides for individual focus adjustment of therespective lens systems independently of each other. By operation of thefocusing adjustment just described with respect to FIG. 15, both lenssystems are focused in unison through the clutch '74-. When this hasbeen accomplished to the satisfaction of the user, he may uncouple theleft-hand (as viewed in FIG. 15) focus adjustment drive rod 6 andcontinue to operate the focus wheel 63 to adjust the right hand prism 53independently. The means for accomplishing this result is best seen inFIGS. 13 and 14 and comprises an externally accessible button fill whichwhen pressed, rotates a bell crank 82 about its pivot 83. The end of thebell crank 32 is connected by tangs 85 to the gear 72. Element '73 itwill be remembered is spring-biased into meshing engagement with thefixed clutch portion 72, but when the button 81 is depressed, the bellcrank 82 will separate the element 73 from the portion 72 and rotationof the focus Wheel 66 effects only actuation of the right hand prismshown in FIG. 15.

- As best seen in FIGS. l5, l6 and 17, a mechanism is provided inassociation with the disclosed focusing adjustment, to permit the userof the binocular to record or indicate for later reference the precisefocus setting which for him is the correct long distance adjustment. Forthis purpose, a detent gear @il having a stop 9W is freely rotatableabout the drive shaft 67 and has attached to its upper surface a disc91. The latter defines at one point in its periphery a detent or recess92. Immediately above the disc 91 and freely rotatable with respect toit and the detent gear Jill, is a follower disc 93 carrying a stop armThe focus wheel on its underside defines a rectangular recess 95.Mounted within the recess 95 is a slide '96 which has a slot 97 topermit lateral movement of the slide relative to drive shaft 67. Theslide 96 is biased toward the left as shown in FIGS. 16 and 17 by aspring lying between the shaft 67 and an integral lug 99 forming aportion of the slide 956. The slide 96 at its edge opposite the lug 9*has a downturned lug or nose ftlti. The relationship of the componentparts is such that the nose Mill is adapted to ride along the peripheryof the disc 91 and being urged toward the left by the spring 98, thenose fill? will drop into the detent 92 when the focusing wheel movesthe slide in a position adjacent to the detent. Thereafter, the rotationof the focus wheel as will also rotate the detent gear 9d unless thedetent gear is prevented from rotation.

The detent gear may be selectively prevented from rotation with shaft 67by engagement with teeth of a registering lever 1M. The lever Iltll hasa projecting tab M32 which extends externally of the central bridge 13immediately below the focus wheel. When the user of the binocular hasobtained his own individual long distance focus adjustment, and wishesto register or record the place at which this adjustment was made, hemerely depresses the tab 1G2 which will cause the registering leverltlil to rotate about the pivot iii?) and the teeth of the lever 10 1will engage the teeth'of the detent gear 90.

The detent lever MP1 has a key-hole shaped slot 1%. A

7 spring-loaded button 105 (FIG. 18) has a smaller cylindrical section106 corresponding to the narrow portion of the slot 104 and a largercircular section 107 which corresponds to the larger diameter section ofthe slot 104. Therefore, with the lever 101 in its dotted line position,

the button 105 will be located within the narrow end.

of the slot 104 with the large diameter portion 107 held beneath thesurface of the lever 101 (as shown in FIG. 18). A spring 109 normallymaintains the lever 101 in the dotted line position with the tab 102protruding from the central support. When however, the user wishes tomove the detent lever 101 into engagement with the detent gear 90, hemay push the tab 102 and the lever 101 will be moved into its solid lineposition. The button 105 will also be moved to the lower end of the slot104 and due to spring 110, the portion 107 of the button will be forcedinto the larger diameter section of the slot 104, thereby holding theregistering lever 101 in engagement with the gear 90.

However, the user may, notwithstanding the positioning of the nose 100within the detent 92, rotate the focus wheel 66 to force the slide 96and the nose 100 to move against the spring 98. The nose 100 will thenagain 7 travel around the periphery of the disc 91. If the nose is movedclockwise about the disc 91, which is in the direction of short rangefocus adjustment, the nose 100 will not thereafter drop into the detent92 after 360 of travel because the nose 100 will also travel around thefollower disc 93 and against the arm 94 thereof. The latter will stop byabutment against stop since that portion of the follower disc 93adjacent arm 94 has a radius equal to the radius of the disc 91, thefollower disc will in effect prevent the nose from dropping into thedetent 92. However, when the nose is moved counterclockwise relative tothe disc 91 or in a direction back toward long-range focus adjustment,the nose 100' will drop into the detent 92 upon coming to a positionadjacent to the detent, which will serve as an indication to the userthat he has arrived at the long range focus position.

Assembly and mounting of the optical elements As illustrated, in FIGS. 3and 8 the lenses of the ocular lens unit 16 are cut segmentally exceptfor the eyepiece lens 16. The same applies to the spacers 115, betweenthe individual lenses. The ocular lens unit is mounted in a housing 17which has a bevelled recess boarded by surfaces 117, 118. Surface 118proceeds into the plane of the drawing at a 45 (FIG. 8) angle and servesas a bearing surface for the base (hypotenuse) of prism 52 (FIG. 12). Inaddition rectangular aperture stops 119, 120 are provided for imagefield limitation of the ocular lens unit and prism 52 at the end of thehousing 17.

During assembly of the component parts thus far described, the prism 52,the individual lenses of the ocular lens unit together with the spacers115, 115' are placed into the housing 42 with an additional spacingmember 121 which abuts the circular eyepiece lens 116. The circular eyelens 116 is forced into a position of engagement with the spacing member121 and the spacer 115 by a threaded cylindrical collar 122; The latteris appropriately recessed at 123 to receive a portion of the lens 116'and threadably engages the housing 17. The latter is secured adj-ustablyto the body of the lens casing by screws 17 (FIGS. 5 and 10).

The prism 53 is locked against rotation by providing the mount 58therefore with a guide groove 124 paralleling the optical axis asindicated in FIGS. 12 and 15. The mount 58 is engaged by a finger 125which blocks the mount 58 against rotation. The finger 125 is formed asan eccentric extention of stud 126 so that rotation of stud 126 foradjustment purposes allows the mount 58 to turn to an extent about theoptical axis. The stud 126 is itself secured against further turning,after adjustment, by rotation of a set screw 127.

As mentioned, light is received from an objective lens 50 by a mirror51. The mirror is inclined with respect to the incident light at anangle of 45 and is adjustable with respect thereto. The mirror issecured in a mount 128 which in turn is secured to a resilient orspring-like member 129 secured to a base plate 130. Provided in the baseplate 130 are two set screws 131 in suitably threaded bores serving asan abutment for the member 129. Hence, adjusting the set screws 131 willresult in a perpendicular adjustment of the mirror 51, to the lightpath. Also provided in the frame 42 are openings 132 to render thescrews 131 accessible from without.

Moreover, base plate 130 is secured rotatably to the frame 42 by ashoulder screw 133. The side of base plate 130 further is engaged by twoset screws 134, 134 to fix the base plate in a given position ofrotation about a circular extension on the frame 42. Thus, an adjustmentof these screws 134, 134' will result in rotating the mirror about theaxis of screw 133. By the foregoing adjustments, the mirror can beadjusted in two planes independently.

For purposes of mounting the objective lens unit 16, the unit is heldwithin the lens mount 55 within a bore which at its rear end has a stop135 for the objective lens mount. The objective lenses are held by themount 55 attached to housing 4 2, and a closing frame 136 which isscrewed onto the mount 55. At the same time, the frame 136 serves as aguide rail for the objective shutter.

It will be understood that the foregoing description relates to aparticular embodiment and is therefore merely representative.Consequently, changes may be made therefrom without departing from theteachings of the invention. In order fully to appreciate the spirit andscope of the invention, reference should be made to the appended claimsin which:

We claim:

1. In combination with a binocular telescope comprising lens casings,lens optical filters movable across an optical path through a casing andmovable into the casing outside of the optical path comprising a filterframe for holding each of said filters, means defining a groove normalto the optical axis, a portion of said frame being slidable in saidgroove to guide the frame during movement thereof normal to said axis, ahousing structure defining a vertical groove, an externally operableactuating member slidable in said vertical groove connected to saidframe, a disc pivotally connected to said actuating member outwardly tosaid housing, a plate positioned outwardly adjacent to said disc anddefining a vertical slot for the passageof said actuating member, saidplate also defining a generally horizontal slot for receiving a pinattached to said disc, said pin and the horizontal slot causing rotationof said disc about the actuating member upon vertical movement of saidactuating member, said disc thereby covering the groove in the housingand the vertical slot in the plate during all positions of the filter,and a spring mounted in the lens casing and bearing against edgeportions of said disc, the edge portions of the disc being shaped inrelation to the spring such that when the filter frame is moved over acenter position, the frame is resiliently urged into a terminalposition.

2. The binocular telescope combination of claim 1 in which the opticalaxis is inclined respective of a horizontal axis through the lens casingand means are provided in connecting the actuating member to the framefor permitting relative movement therebetween during the respectivemovements of the frame and the actuating memher.

3. In combination with a binocular telescope comprising two box-likelens casings transversely movable over a central support, said casingsbeing movable from closed positions where the casings completely envelopthe support to open positions for interpupillary distance accommodation,lens optical filters movable across an optical path through a casing andmovable into the casing out- Side of the optical path comprising, afilter frame for holding each of said filters, means defining a groovenormal to the optical axis, said axis being inclined respective of ahorizontal axis through a lens casing, a portion of said frame beingslidable in said groove to guide the frame during movement thereofnormal to said axis, a housing structure defining a vertical groove, ahollow button receptacle slidable in said vertical groove, meansconnecting the receptacle to the frame to permit relative movementtherebetween during vertical movement of the receptacle and slidablemovement of the frame, a disc pivotally connected to said receptacleoutwardly of said housing, a plate positioned outwardly adjacent to saiddisc and defining. a generally horizontal slot for receiving a pinattached to said disc, said pin and the horizontal slot causing rotationof said disc about the receptacle upon vertical movement of saidreceptacle, a button slidable in said receptacle and a spring in saidreceptacle for normally urging said button outwardly thereof to aposition external to the lens casing, said casings when in closedpositions urging the button inwardly of the receptacle, said platedefining a vertical slot for the passage of said button, said discduring its rotation covering the groove in the housing and the verticalslot in the plate during all positions of the filter, a spring mountedin the lens casing and bearing against edge portions of said disc, theedge portions of the disc being shaped in relation to the spring suchthat when the filter frame is moved over a center position the frame isresiliently urged into a terminal position.

4. In combination with a binocular telescope comprising lens casings,lens optical filters movable across an optical path through a casing andmovable into the casing outside of the optical path comprising, a filterframe for holding each of said filters, casing structure defining afirst groove means for receiving an extending part of said frame toguide said frame along an axis normal to the optical axis, an externallyaccessible slidable actuating member connected to said frame, saidcasing defining a second groove means permitting a portion of saidactuating member to protrude from the casing, means covering saidpassage means against the ingress of foreign material into the casing inall positions of the actuating member, said covering means including aresilient overce'nter mechanism for urging said actuating member and theframe into one of two terminal positions.

5. The combination according to claim 4 in which each of said lenscasings has a longitudinal axis of symmetry lying generally parallel toand intermediate the top and bottom surfaces of said casing, the opticalaxis through the lens casing is inclined respective of said longitudinalaxis, said actuating member causing the filter frame to move along anaxis normal to the optical axis, means for guiding the movement of theactuating member and means for connecting the actuating member to theframe for permitting relative movement therebetween during therespective movements of the frame and the actuating member.

6. A binocular telescope comprising (1) lens casings, each of saidcasings having a longitudinal axis of symmetry lying generally parallelto and intermediate the top and bottom surfaces of said casing, (2) alens optical system within each of said casings, the optical axisthrough the lens casing being inclined respective of said longitudinalaxis, (3) lens optical filters movable within said casing into or out ofan optical path, each of said filters having a filter frame for holdinga filter, means guiding said frame for movement normal to the opticalaxis, an externally accessible, slidable actuating member connected tosaid frame, casing structure defining a passage means permitting aportion of said actuating member to protrude from the casing and beguided therein, means covering said passage means against the ingress offoreign material into the casing in all positions of the actuatingmember, said covering means including a resilient over-center mechanismfor urging said actuating member and the frame into one of two terminalpositions, and means for permitting relative movement between the frameand the actuating member during the respective movements therebetween.

References Cited by the Examiner FOREIGN PATENTS 431,692 7/1935 GreatBritain.

JEWELL H. PEDERSEN, Primary Examiner.

4. IN COMBINATION WITH A BINOCULAR TELESCOPE COMPRISING LENS CASING, LENS OPTICAL FILTERS MOVABLE ACROSS AN OPTICAL PATH THROUGH A CASING AND MOVABLE INTO THE CASING OUTSIDE OF THE OPTICAL PATH COMPRISING, A FILTER FRAME FOR HOLDING EACH OF SAID FILTERS, CASING STRUCTURE DEFINING A FIRST GROOVE MEANS FOR RECEIVING AN EXTENDING PART OF SAID FRAME TO GUIDE SAID FRAME ALONG AN AXIS NORMAL TO THE OPTICAL AXIS, AN EXTERNALLY ACCESSIBLE SLIDABLE ACTUATING MEMBER CONNECTED TO SAID FRAME, SAID CASING DEFINING A SECOND GROOVE MEANS PERMITTING A PORTION OF SAID ACTUATING MEMBER TO PROTRUDE FROM THE CASING, MEANS COVERING SAID PASSAGE MEANS AGAINST THE INGRESS OF FOREIGN MATERIAL INTO THE CASING IN ALL POSITIONS OF THE ACTUATING MEMBER, SAID COVERING MEANS INCLUDING A RESILIENT OVERCENTER MECHANISM FOR URGING SAID ACTUATING MEMBER AND THE FRAME INTO ONE OF TWO TERMINAL POSITIONS. 